On Jan. 23 the FAA issued
Airworthiness Directive (AD) No. 2012-17-08 applicable to Bell Helicopter Textron Inc. (Bell) Model 204B, 205A, 205A-1, 205B and 212 helicopters with a main rotor yoke, part number (P/N) AAI-4011-102 (all dash numbers), ASI-4011-102 (all dash numbers), or 204-011-102 (all dash numbers), installed. The AD defines the unsafe condition as a crack in the yoke. This condition could result in failure of the yoke and subsequent loss of helicopter control.
This AD supersedes four ADs related to the main rotor yoke on the effected helicopters and retains certain inspections and certain life limits, requires an increased inspection frequency for certain yokes and expands these inspections and retirement to other yokes. FAA published a notice of proposed rulemaking (NPRM) on Nov. 2, 2011 proposing to supersede AD 79-20-05 with amendments dated Jan. 31, 1980, Dec. 6, 1979 and Sep. 27, 1979; AD 81-19-01 dated Sep. 14, 1981; AD 81-19-02 dated Sep. 14, 1981; and AD 93-05-01 dated Mar. 15, 1993. No comments were received from the public on the NPRM.
Compliance with the AD depends on the part number of the yoke installed, time in service (TIS), and the type of aircraft use. Refer to the explanation and Table 1 in the AD to calculate factored hours TIS in order to determine required action.
The AD is effective Feb. 27, 2013. NAAA recommends you read the AD carefully to determine the action or actions required to comply with this AD. Click here to read or download the document.